Sliding parallel rule

ABSTRACT

A parallel rule includes an elongated body and an elongated arm with a crosshead which is slidingly inserted into a longitudinally extending channel in the body for longitudinal movement of the arm relative to the body at a desired angle thereto. To allow the rule to be carried in a person&#39;&#39;s pocket, the crosshead can be slid from the channel and the arm then slid bodily into the channel. With the arm so disposed in the channel, the rule can also be used as a slide rule.

United States Patent Palfi [4 Jan. 18, 1972 154] SLIDING PARALLEL RULE [72] inventor: Leslie Palil, 167 Bayview Heights Drive,

Toronto 17, Ontario, Canada [22] Filed: Dec. 10, 1970 211 Appi. No.: 96,763

[521 0.8. CI. .Q ..235/70 R, 33/103 [51] Int. Cl. .G04b 27/02, B431 7/06 [58] Field oiSearclr ..235/70 R, 70 A; 33/103, 102, 33/101, 114

i [56] References Cited UNITED STATES PATENTS 761,707 6/ 1 904 Peyman ..220/42 888,070 5/1908 Dissell ....33/103 1,623,117 4/1927 Holland ....33/l03 2,893,126 7/1959 Coallier.... ....33/103 3,443,749 5/1969 Cimetta ..235/70 R FOREIGN PATENTS OR APPLICATIONS 898,522 11/1953 Germany ..235/70 615,172 1/1961 ltaly..... 635,019 2/1962 Italy ..33/103 Primary Examiner-Richard B. Wilkinson Assistant Examiner-Stanley A. Wai Attorney-J. Noel Walton [57] ABSTRACT A parallel rule includes an elongated body and an elongated arm with a crosshead which is slidingly inserted into a longitudinally extending channel in the body for longitudinal movement of the arm relative to the body at a desired angle thereto. To allow the rule to be carried in a person's pocket, the crosshead can be slid from the channel and the arm then slid bodily into the channel. With the arm so disposed in the channel, the rule can also be used as a slide rule.

9 Claims, 6 Drawing Figures 1 SLIDING PARALLEL RULE BACKGROUND OF THE INVENTION The present. invention relates, to drawing instrumentsand parallel rule or a sliding T-square.

Various proposals for the construction 'of parallel rules of the type with which this invention is concerned have heretofore been made but all the previously proposed rulesuhave presented the disadvantage that they are rather cumbersome and awkward'and cannot be carried in aperson3s pocket.

It is. accordingly a'principal object of this invention toprovide a parallel rule or sliding T-square which is constructed in ..such a way that it can be readily reassembled into a more com- -pact configuration in which it is then easily c'arried, for. example, in a pocket.

Another object of this invention, in. accordance with a.useful but optional feature thereof, is to provide a-sliding parallel rule which is constructed so that it can also be usedas a;slide rule for making mathematical calculations. Other objects of. the invention will become. apparent as. the description herein proceeds.

SUMMARY OF THE INVENTION Broadly, the present invention provides arparallelrule 'which comprises an elongated body; an elongatedarm; first guide means on.said elongatedarm and-extending generally longitudinally relative thereto; second guidemeans on .said elongated arm and extending angularly relative thereto; .and longitudinally extending guide means on said. elongated. body and dimensioned for slidingly mating withusaid first and second guide means on said elongated arm for sliding movement of said elongated armlongitudinally along said elongated body when either of said first and second guide-means on said elongated arm is mated with said guide means .on said'elongated body whereby, when said first guide means on said elongated arm, is slidinglymated with said guide means on.said

.elongated body, saidzelongatedarm is-disposed generally construction, a parallel rule in accordance withthis invention is usefully constructed so that, when,the first guidemeans on itselongated arm is slidingly mated with the. guide means on its elongated body, the rule can also. be utilized as .a slide rule so enabling the user to make mathematical calculations ofv one kind .or another.

Other features andadvantages of the invention will. become apparent as the description herein proceeds.-

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described merely by way of illustration with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of one embodiment of a parallel rule in accordance with the; present invention and illustrating the manner in which that rule is used as a parallel rule or sliding T-square;

FIG. 2 is a fragmentary vertical sectional'view through the ink of FIG. 1 when taken as indicated by the arrows 2-2 of that FIG.;

FIG. 3 is a perspective view of the ruleof FIGS. 1 'and':2 when reassembled into its carrying'configuration in which it is easily carried in a person s pocket and .also showing ,the manner in which that rule is usefully constructed so as' to'have a slide rule function;

FIG..4 is a vertical sectional view through the rule of FIGJ3 when taken as indicated by the arrows 4--4 thereon;

FIG..-5 is a fragmentary. perspectiveview of an alternative -embodimentof a sliding parallel rule inaccordance with this invention; and

FIG.'.6 is a fragmentary vertical secti onal view through the .1 parallel rule shown in FIG. 5 whentaken .asindicated by the arrows 6--6 of that FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to the sliding parallel rule generally indicated at 10 in FIGS. 1 to 4 of the accompanying drawings, it will-be seen therefrom that the rule comprises a generally rectangular elongated body generally indicated at 11 and a generally rectangular elongated arm-generally indicated atl2. As will be explained in greater detail hereinafter, suitable guide means are provided on both the body 11 and the arm 12 so that these two members can be slidinglymated, as required, in the two relative positions shown in FIGS. 1 and 3.

In the particular embodiment of .a rule as shown in FIGS. 1 to 4, a single guide means is provided on the elongated body 11 of the rule 10. Thisguide meansis in the form of a longitudinally extending recess or channel .indicated at '14 and defined by generally parallel upstanding sidewalls l5 and 16 which are. spaced apart a distance a essentially equal to the width between upstanding side edge surfaces 17 and 18 of the arm 12. In this way, the arm. 12 can be inserted into the channel-14 for longitudinal sliding movement therein and as actually illustrated in FIGS. 3 and 4.

For the purpose of retaining the .arm' 12 within the. channel .14 of the body 11 against upward movement therefrom, the sidewalls l5 and 16 of the channel 14, on the other hand, and the side edge surfaces 17 and- I8 of the arm 12, on the other hand, are provided with longitudinally extending and mating guide tongues and guideways. In the particular rule 10 shown in FIGS. 1 to 4, the elongated arm 12 is formed in its upstandingside edges17 and 18 with transversely projecting and longitudinally extending tongues 20 and 21 respectively. When I the arm 12 is slid into the channel 14, these tongues 20 and. 21 are slidingly. received within guideways 22 and 23 respectively formed in the sidewalls 15 and 16 respectively defining'the channel 14 as will .be readily understood by .particular reference to FIG. 3 of theaccompanying-drawings.

In accordance with a useful but optional feature'of this invention, the body 11 and the arm l2v have planar top surfaces 25. and 26 respectively and the arm .12 is formed so as to have .a thickness b (FIGS. 2 and 4) which is generally equal to the .depth of the aforementioned channel 14. In this way, when the .-arm 12 is slid into the channel l4.as shown in FIGS. 3 and 4 for longitudinal sliding movement therein, the top surface 26 .of the arm 12 is generallycoplanar with the topsurface 25 of the body .11. Indicia 27 and 28 are printed, etched or otherwise. provided on the top .surfaces'25 and 26 respectively of thebody ll-and the arm 12. respectively sov that the rule 10 can'be usedas a slide rule forthepurpose of making mathelmatical calculations of one kind or another. For thispurpose, therule I0 is providedwith a transparent cursor generally indicated at 30 and of any appropriate conventional construction.

Inaddition to the first guide means constituted by its edge surfaces 17 and '18, the elongated arm 12 is formedwith a :second. guide meanswhich, in the rule 10 shown in FIGS. .1 to

4, is constituted by a crosshead generally indicated at 32 and which isdimensioned so as to be guidi'ngly receivable within gated arm 12 by an upstanding member 39. To stabilize the position of the arm 12 when the crosshead 32 is disposed within the channel 14 of the body 11, the upstanding member 39 is formed with an upright surface 40 which slidingly abuts an appropriate side edge 41 or 42 of the elongated body 11.

It will be seen from FIGS. 1 and 2 that the elongated body 11, the elongated arm 12, the crosshead 32, the extension 38 and the upstanding member 39 are dimensioned so that, when the crosshead 32 is correctly disposed within the channel 14, the undersurface 43 of the arm 12 is generally coplanar with the undersurface 44 of the body 11. The manner in which the rule 10 is used as a sliding parallel rule or square will now be readily understood.

Although a particularly important practical advantage of the rule 10 shown in FIGS. I to 4 is that it can be used either as a parallel rule or as a slide rule, this dual function is not an essential feature of the present invention and is provided only in accordance with a preferred feature thereof. A primary advantage of the rules of this invention is that the arm 12 of such a rule I can be removed from its normal transversely projecting disposition and the rule reassembled so that the arm is then disposed generally parallel to the body. In this way, such a rule is particularly compact and is easily carried in a persons pocket.

In accordance with another useful but still optional feature of this invention, the elongated arm 12 of the rule 10 is formed from an optically transparent material and, although the rule 10 has been shown as having the arm 12 projecting generally perpendicularly from the body 11 when the crosshead 32 is disposed within the channel 14, it is equally within the'scope of this invention to construct the rule 10 so that the arm 12 thereof extends from the body at any other desired angle. Alternatively, if desired, such a rule can be constructed so that the angular disposition of the arm relative to the body can be adjusted as desired.

An alternative construction for a parallel rule in accordance with this invention is generally indicated at 50 in FIGS. and 6 of the accompanying drawings. The rule 50 is generally similar to the parallel rule already described herein in that it comprises an elongated body generally indicated at 51 and an elongated arm generally indicated at 52 and which can be disposed slidingly in a longitudinally extending channel 54 formed in the body 51 or which can be supported so that it extends angularly from the body 51 as actually shown in FIGS. 5 and 6.

For retaining the arm 52 in position in the channel 54, the latter is defined by upstanding and parallel spaced-apart sidewalls 55 and 56 which are formed with longitudinally extending and inwardly projecting guide tongues 57 and 58 respectively. These tongues 57 and 58 are slidingly received in guideways 59 formed in upstanding side edge surfaces 60 of the arm 52.

In one of its end surfaces, the elongated arm 52% fonned with a transversely extending generally tubular guide member 64 which is slidingly received within either of two keyhole-section guide channels 65 and 66 formed in opposite side edges 67 and 68 of the elongated body 51.

It will be understood that the rule 50 can usefully be constructed for use as a slide rule as was the case for the rule 10 shown in FIGS. 1 to 4. In such a case, the body 51 and the arm 52 are provided with appropriate indicia and the rule 50 will also comprise a suitable cursor 61 which is not shown in FIG. 5.

What is claimed is:

1. A parallel rule which comprises an elongated body; an elongated arm; first guide means on said elongated arm and extending generally longitudinally relative thereto; second guide means on said elongated arm and extending angularly relative thereto; and longitudinally extending guide means on said elongated body and dimensioned for slidingly mating with said first and second guide means on said elongated arm for sliding movement of said elongated arm longitudinally along said elongated body when either of said first and second guide means on said elongated arm is mated with said guide means on said elongated body whereby, when said first guide means on said elongated arm is slidingly mated with said guide means on said elongated body, said elongated arm is disposed generally parallel to said elongated body for sliding longitudinal movement relative thereto in mated engagement therewith and whereby, when said second guide means on said elongated arm is slidingly mated with said guide means on said elongated body, said elongated arm extends angularly relative to said elongated body for sliding movement longitudinally relative thereto and in mated engagement therewith.

2. A parallel rule as claimed in claim I in which said elongated arm has a supporting undersurface, in which said elongated body has a generally planar supporting under'surface, and in which said second guide means on said elongated arm and said guide means on said elongated body are dimensioned and disposed so that said supporting undersurfaces of said elongated body and'of said elongated arm are in generally coplanar disposition when said second guide means on said elongated arm and said guide means on said elongated body are slidingly mated.

3. A parallel rule as claimed in claim 1 which additionally comprises a cursor slidingly disposed on said elongated body and in which said elongated body and said elongated arm have cooperating indicia provided thereon so that, when said first guide means on said elongated arm is slidingly mated with said guide means on said elongated body, said parallel rule functions as a slide rule.

4. A parallel rule as claimed in claim 1 in which said first and second guide means on said elongated arm is each dimensioned slidingly to mate with a single said guide means on said elongated body and in which said second guide means on said elongated arm is disposed upwardly of a supporting undersurface of said elongated arm.

5. A parallel rule as claimed in claim 4 in which said guide means on said elongated body comprises transversely spacedapart and parallel upstanding walls defining a longitudinally extending channel dimensioned longitudinally slidingly to receive said elongated arm, in which said elongated ann comprises generally parallel and spaced-apart upstanding side edge surfaces constituting said first guide means and adapted slidingly to mate with corresponding ones of said upstanding walls of said longitudinally extending channel in said elongated body, and in which said upstanding walls of said longitudinally extending channel in said elongated body and said upstanding side edge surfaces of said elongated arm are formed with slidingly cooperating guide flanges and guideways for restricting upward movement of said elongated arm out of said longitudinally extending channel when said elongated arm is slidingly disposed therewithin.

6. A parallel rule as claimed in claim 5 in which said elongated body and said elongated arm are provided on top surfaces thereof with cooperating indicia, and which parallel rule additionally comprises a cursor slidingly disposed on said elongated body, whereby said parallel rule can also be used as a slide rule.

7. A parallel rule as claimed in claim 6 which said second guide means on said elongated arm has a spaced-apart generally parallel upstanding side edge surfaces slidingly mating with said upstanding walls of said longitudinally extending channel in said elongated body when said second guide means of said elongated arm is disposed within said longitudinally extending channel in said elongated body, and in which said longitudinally extending side edge surfaces of said second guide means and said upstanding walls of said longitudinally extending channel in said elongated body are provided with cooperating guide flanges and guideways to restrict upward movement of said second guide means out of said longitudinally extending channel when said second guide means is slidingly disposed within said longitudinally extending channel whereby said elongated arm is slidingly mated with said elongated body at a desired angle relative thereto.

slidingly disposed within said longitudinally extending channel in said elongated body thereby to stabilize the angular disposition of said elongated arm relative to said elongated body.

9. A parallel rule as claimed in claim I in which said elongated arm is optically transparent.

t I I! t i 

1. A parallel rule which comprises an elongated body; an elongated arm; first guide means on said elongated arm and extending generally longitudinally relative thereto; second guide means on said elongated arm and extending angularly relative thereto; and longitudinally extending guide means on said elongated body and dimensioned for slidingly mating with said first and second guide means on said elongated arm for sliding movement of said elongated arm longitudinally along said elongated body when either of said first and second guide means on said elongated arm is mated with said guide means on said elongated body whereby, when said first guide means on said elongated arm is slidingly mated with said guide means on said elongated body, said elongated arm is disposed generally parallel to said elongated body for sliding longitudinal movement relative thereto in mated engagement therewith and whereby, when said second guide means on said elongated arm is slidingly mated with said guide means on said elongated body, said elongated arm extends angularly relative to said elongated body for sliding movement longitudinally relative thereto and in mated engagement therewith.
 2. A parallel rule as claimed in claim 1 in which said elongated arm has a supporting undersurface, in which said elongated body has a generally planar supporting undersurface, and in which said second guide means on said elongated arm and said guide means on said elongated body are dimensioned and disposed so that said supporting undersurfaces of said elongated body and of said elongated arm are in generally coplanar disposition when said second guide means on said elongated arm and said guide means on said elongated body are slidingly mated.
 3. A parallel rule as claimed in claim 1 which additionally comprises a cursor slidingly disposed on said elongated body and in which said elongated body and said elongated arm have cooperating indicia provided thereon so that, when said first guide means on said elongated arm is slidingly mated with said guide means on said elongated body, said parallel rule functions as a slide rule.
 4. A parallel rule as claimed in claim 1 in which said first and second guide means on said elongated arm is each dimensioned slidingly to mate with a single said guide means on said elongated body and in which said second guide means on said elongated arm is disposed upwardly of a supporting undersurface of said elongated arm.
 5. A parallel rule as claimed in claim 4 in which said guide means on said elongated body comprises transversely spaced-apart and parallel upstanding walls defining a longitudinally extending channel dimensioned longitudinally slidingly to receive said elongated arm, in which said elongated arm comprises generally parallel and spaced-apart upstanding side edge surfaces constituting said first guide means and adapted slidingly to mate with corresponding ones of said upstanding walls of said longitudinally extending channel in said elongated body, and in which said upstanding walls of said longitudinally extending channel in said elongated body and said upstanding side edge surfaces of said elongated arm are formed with slidingly cooperating guide flanges and guideways for restricting upward movement of said elongated arm out of said longitudinally extending channel when said elongated arm is slidingly disposed therewithin.
 6. A parallel rule as claimed in claim 5 in which said elongated body and said elongated arm arE provided on top surfaces thereof with cooperating indicia, and which parallel rule additionally comprises a cursor slidingly disposed on said elongated body, whereby said parallel rule can also be used as a slide rule.
 7. A parallel rule as claimed in claim 6 which said second guide means on said elongated arm has a spaced-apart generally parallel upstanding side edge surfaces slidingly mating with said upstanding walls of said longitudinally extending channel in said elongated body when said second guide means of said elongated arm is disposed within said longitudinally extending channel in said elongated body, and in which said longitudinally extending side edge surfaces of said second guide means and said upstanding walls of said longitudinally extending channel in said elongated body are provided with cooperating guide flanges and guideways to restrict upward movement of said second guide means out of said longitudinally extending channel when said second guide means is slidingly disposed within said longitudinally extending channel whereby said elongated arm is slidingly mated with said elongated body at a desired angle relative thereto.
 8. A parallel rule as claimed in claim 7 in which said elongated body has spaced-apart and generally parallel upstanding side edge surfaces and in which said elongated arm is formed with a transverse upstanding surface adapted slidingly to abut one of said upstanding side edge surfaces of said elongated body when said second guide means on said elongated arm is slidingly disposed within said longitudinally extending channel in said elongated body thereby to stabilize the angular disposition of said elongated arm relative to said elongated body.
 9. A parallel rule as claimed in claim 1 in which said elongated arm is optically transparent. 